One type of electrical switch, described in U.S. Pat. No. 6,323,449, includes a contact plate that forms a plurality of blade that can be downwardly deflected against stationary terminals on a support. The contact blades are moved down by a tripper, and especially a snap tripper which includes a center portion that suddenly snaps down when it is depressed by a predetermined distance. In the earlier patent, the snap tripper was of rectangular shape and lay above the contact blades, and when the tripper was depressed it suddenly snapped down and downwardly deflected the contact blades. A snap tripper is desirable to provide tactile feedback to indicate when the switch has closed. It would be desirable if a switch could be provided with a contact plate having contact blades that suddenly moved down against terminals, without requiring the tripper to actually push down the contact blades.
In accordance with one embodiment of the present invention, an improved electrical switch is provided, of the type that includes a plurality of terminals mounted on an insulative support, a contact plate having blades lying over the terminals, and a tripper with a center portion that snaps down. The tripper center portion lies below the contact plate center portion instead of above it. When the contact plate center portion is depressed, it and the tripper center portion slowly move down until the tripper suddenly snaps down and the contact plate also snaps down. This causes the blades of the contact plate to suddenly move down against the terminals to close switch portions of the switch.
The tripper can be of the efficient dome shape with a largely circular periphery. The contact blades of the contact plate have free ends that extend beyond the periphery of the tripper, so the tripper does not lie in the way of movement of the free ends of the blades against the terminals. The contact plate has a pair of stabilizing branches that are permanently bent at downward inclines so their free ends are positioned by the support to thereby fix the orientation of the contact plate.
The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.